[add] wip service worker & offline reader

README.md

@@ -42,8 +42,9 @@ In additional to the compatible KOSync API's, we add:
 - Additional APIs to automatically upload reading statistics
 - Upload documents to the server (can download in the "Documents" view or via OPDS)
 - Book metadata scraping (Thanks [OpenLibrary](https://openlibrary.org/) & [Google Books API](https://developers.google.com/books/docs/v1/getting_started))
-- No JavaScript for the main app! All information is generated server side with go templates.
+- Limited JavaScript use. Server-Side Rendering is used wherever possible. The main app is fully operational without any JS. JS is only required for:
-  - JavaScript is used for the ePub reader. Goals to make it service worker to enable a complete offline PWA reading experience.
+  - EPUB Reader
+  - Offline Mode / Service Worker
 
 # Server
 
@@ -76,25 +77,24 @@ The service is now accessible at: `http://localhost:8585`. I recommend registeri
 
 ## Configuration
 
-| Environment Variable | Default Value | Description                                                          |
+| Environment Variable | Default Value | Description                                                         |
-| -------------------- | ------------- | -------------------------------------------------------------------- |
+| -------------------- | ------------- | ------------------------------------------------------------------- |
-| DATABASE_TYPE        | SQLite        | Currently only "SQLite" is supported                                 |
+| DATABASE_TYPE        | SQLite        | Currently only "SQLite" is supported                                |
-| DATABASE_NAME        | bbank         | The database name, or in SQLite's case, the filename                 |
+| DATABASE_NAME        | book_manager  | The database name, or in SQLite's case, the filename                |
-| DATABASE_PASSWORD    | <EMPTY>       | Currently not used. Placeholder for potential alternative DB support |
+| CONFIG_PATH          | /config       | Directory where to store SQLite's DB                                |
-| CONFIG_PATH          | /config       | Directory where to store SQLite's DB                                 |
+| DATA_PATH            | /data         | Directory where to store the documents and cover metadata           |
-| DATA_PATH            | /data         | Directory where to store the documents and cover metadata            |
+| LISTEN_PORT          | 8585          | Port the server listens at                                          |
-| LISTEN_PORT          | 8585          | Port the server listens at                                           |
+| REGISTRATION_ENABLED | false         | Whether to allow registration (applies to both WebApp & KOSync API) |
-| REGISTRATION_ENABLED | false         | Whether to allow registration (applies to both WebApp & KOSync API)  |
+| COOKIE_SESSION_KEY   | <EMPTY>       | Optional secret cookie session key (auto generated if not provided) |
-| COOKIE_SESSION_KEY   | <EMPTY>       | Optional secret cookie session key (auto generated if not provided)  |
+| COOKIE_SECURE        | true          | Set Cookie `Secure` attribute (i.e. only works over HTTPS)          |
-| COOKIE_SECURE        | true          | Set Cookie `Secure` attribute (i.e. only works over HTTPS)           |
+| COOKIE_HTTP_ONLY     | true          | Set Cookie `HttpOnly` attribute (i.e. inacessible via JavaScript)   |
-| COOKIE_HTTP_ONLY     | true          | Set Cookie `HttpOnly` attribute (i.e. inacessible via JavaScript)    |
 
 ## Security
 
 ### Authentication
 
 - _Web App / PWA_ - Session based token (7 day expiry, refresh after 6 days)
-- _KOSync & SyncNinja API_ - Header based (KOSync compatibility)
+- _KOSync & SyncNinja API_ - Header based - `X-Auth-User` & `X-Auth-Key` (KOSync compatibility)
 - _OPDS API_ - Basic authentication (KOReader OPDS compatibility)
 
 ### Notes
@@ -119,7 +119,7 @@ go install github.com/sqlc-dev/sqlc/cmd/sqlc@latest
 Run Development:
 
 ```bash
-CONFIG_PATH=./data DATA_PATH=./data go run main.go serve
+CONFIG_PATH=./data DATA_PATH=./data REGISTRATION_ENABLED=true go run main.go serve
 ```
 
 # Building
@@ -136,6 +136,16 @@ make docker_build_local
 # Build Docker & Push Latest or Dev (Linux - arm64 & amd64)
 make docker_build_release_latest
 make docker_build_release_dev
+
+# Generate Tailwind CSS
+make build_tailwind
+
+# Clean Local Build
+make clean
+
+# Tests (Unit & Integration - Google Books API)
+make tests_unit
+make tests_integration
 ```
 
 ## Notes

api/api.go

@@ -80,7 +80,6 @@ func (api *API) registerWebAppRoutes() {
 
 	render.AddFromFiles("error", "templates/error.html")
 	render.AddFromFilesFuncs("login", helperFuncs, "templates/login.html")
-	render.AddFromFilesFuncs("reader", helperFuncs, "templates/reader-base.html", "templates/reader.html")
 	render.AddFromFilesFuncs("home", helperFuncs, "templates/base.html", "templates/home.html")
 	render.AddFromFilesFuncs("search", helperFuncs, "templates/base.html", "templates/search.html")
 	render.AddFromFilesFuncs("settings", helperFuncs, "templates/base.html", "templates/settings.html")
@@ -90,7 +89,15 @@ func (api *API) registerWebAppRoutes() {
 
 	api.Router.HTMLRender = render
 
+	// Static Assets (Require @ Root)
 	api.Router.GET("/manifest.json", api.webManifest)
+	api.Router.GET("/sw.js", api.serviceWorker)
+
+	// Offline Static Pages (No Template)
+	api.Router.GET("/offline", api.offlineDocuments)
+	api.Router.GET("/reader", api.documentReader)
+
+	// Template App
 	api.Router.GET("/login", api.createAppResourcesRoute("login"))
 	api.Router.GET("/register", api.createAppResourcesRoute("login", gin.H{"Register": true}))
 	api.Router.GET("/logout", api.authWebAppMiddleware, api.authLogout)
@@ -104,12 +111,12 @@ func (api *API) registerWebAppRoutes() {
 	api.Router.GET("/documents", api.authWebAppMiddleware, api.createAppResourcesRoute("documents"))
 	api.Router.POST("/documents", api.authWebAppMiddleware, api.uploadNewDocument)
 	api.Router.GET("/documents/:document", api.authWebAppMiddleware, api.createAppResourcesRoute("document"))
-	api.Router.GET("/documents/:document/reader", api.authWebAppMiddleware, api.documentReader)
 	api.Router.GET("/documents/:document/file", api.authWebAppMiddleware, api.downloadDocument)
 	api.Router.GET("/documents/:document/cover", api.authWebAppMiddleware, api.getDocumentCover)
 	api.Router.POST("/documents/:document/edit", api.authWebAppMiddleware, api.editDocument)
 	api.Router.POST("/documents/:document/identify", api.authWebAppMiddleware, api.identifyDocument)
 	api.Router.POST("/documents/:document/delete", api.authWebAppMiddleware, api.deleteDocument)
+	api.Router.GET("/documents/:document/progress", api.authWebAppMiddleware, api.getDocumentProgress)
 
 	// Behind Configuration Flag
 	if api.Config.SearchEnabled {

api/app-routes.go

@@ -72,6 +72,18 @@ func (api *API) webManifest(c *gin.Context) {
 	c.File("./assets/manifest.json")
 }
 
+func (api *API) serviceWorker(c *gin.Context) {
+	c.File("./assets/sw.js")
+}
+
+func (api *API) offlineDocuments(c *gin.Context) {
+	c.File("./assets/offline/index.html")
+}
+
+func (api *API) documentReader(c *gin.Context) {
+	c.File("./assets/reader/index.html")
+}
+
 func (api *API) createAppResourcesRoute(routeName string, args ...map[string]any) func(*gin.Context) {
 	// Merge Optional Template Data
 	var templateVarsBase = gin.H{}
@@ -245,7 +257,7 @@ func (api *API) getDocumentCover(c *gin.Context) {
 	// Handle Identified Document
 	if document.Coverfile != nil {
 		if *document.Coverfile == "UNKNOWN" {
-			c.File("./assets/no-cover.jpg")
+			c.File("./assets/images/no-cover.jpg")
 			return
 		}
 
@@ -256,7 +268,7 @@ func (api *API) getDocumentCover(c *gin.Context) {
 		_, err = os.Stat(safePath)
 		if err != nil {
 			log.Error("[getDocumentCover] File Should But Doesn't Exist:", err)
-			c.File("./assets/no-cover.jpg")
+			c.File("./assets/images/no-cover.jpg")
 			return
 		}
 
@@ -309,7 +321,7 @@ func (api *API) getDocumentCover(c *gin.Context) {
 
 	// Return Unknown Cover
 	if coverFile == "UNKNOWN" {
-		c.File("./assets/no-cover.jpg")
+		c.File("./assets/images/no-cover.jpg")
 		return
 	}
 
@@ -317,12 +329,12 @@ func (api *API) getDocumentCover(c *gin.Context) {
 	c.File(coverFilePath)
 }
 
-func (api *API) documentReader(c *gin.Context) {
+func (api *API) getDocumentProgress(c *gin.Context) {
 	rUser, _ := c.Get("AuthorizedUser")
 
 	var rDoc requestDocumentID
 	if err := c.ShouldBindUri(&rDoc); err != nil {
-		log.Error("[documentReader] Invalid URI Bind")
+		log.Error("[getDocumentProgress] Invalid URI Bind")
 		errorPage(c, http.StatusNotFound, "Invalid document.")
 		return
 	}
@@ -333,7 +345,7 @@ func (api *API) documentReader(c *gin.Context) {
 	})
 
 	if err != nil && err != sql.ErrNoRows {
-		log.Error("[documentReader] UpsertDocument DB Error:", err)
+		log.Error("[getDocumentProgress] UpsertDocument DB Error:", err)
 		errorPage(c, http.StatusInternalServerError, fmt.Sprintf("UpsertDocument DB Error: %v", err))
 		return
 	}
@@ -343,15 +355,18 @@ func (api *API) documentReader(c *gin.Context) {
 		DocumentID: rDoc.DocumentID,
 	})
 	if err != nil {
-		log.Error("[documentReader] GetDocumentWithStats DB Error:", err)
+		log.Error("[getDocumentProgress] GetDocumentWithStats DB Error:", err)
 		errorPage(c, http.StatusInternalServerError, fmt.Sprintf("GetDocumentWithStats DB Error: %v", err))
 		return
 	}
 
-	c.HTML(http.StatusOK, "reader", gin.H{
+	c.JSON(http.StatusOK, gin.H{
-		"SearchEnabled": api.Config.SearchEnabled,
+		"id":         document.ID,
-		"Progress":      progress.Progress,
+		"title":      document.Title,
-		"Data":          document,
+		"author":     document.Author,
+		"words":      document.Words,
+		"progress":   progress.Progress,
+		"percentage": document.Percentage,
 	})
 }
 

api/ko-routes.go

@@ -636,7 +636,7 @@ func (api *API) downloadDocument(c *gin.Context) {
 	}
 
 	// Force Download (Security)
-	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filepath.Base(*document.Filepath)))
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", filepath.Base(*document.Filepath)))
 	c.File(filePath)
 }
 

assets/js/idb-keyval.js

@@ -0,0 +1,50 @@
+function _slicedToArray(t,n){return _arrayWithHoles(t)||_iterableToArrayLimit(t,n)||_unsupportedIterableToArray(t,n)||_nonIterableRest()}function _nonIterableRest(){throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.")}function _unsupportedIterableToArray(t,n){if(t){if("string"==typeof t)return _arrayLikeToArray(t,n);var r=Object.prototype.toString.call(t).slice(8,-1);return"Object"===r&&t.constructor&&(r=t.constructor.name),"Map"===r||"Set"===r?Array.from(t):"Arguments"===r||/^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(r)?_arrayLikeToArray(t,n):void 0}}function _arrayLikeToArray(t,n){(null==n||n>t.length)&&(n=t.length);for(var r=0,e=new Array(n);r<n;r++)e[r]=t[r];return e}function _iterableToArrayLimit(t,n){var r=null==t?null:"undefined"!=typeof Symbol&&t[Symbol.iterator]||t["@@iterator"];if(null!=r){var e,o,u=[],i=!0,a=!1;try{for(r=r.call(t);!(i=(e=r.next()).done)&&(u.push(e.value),!n||u.length!==n);i=!0);}catch(t){a=!0,o=t}finally{try{i||null==r.return||r.return()}finally{if(a)throw o}}return u}}function _arrayWithHoles(t){if(Array.isArray(t))return t}function _typeof(t){return _typeof="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(t){return typeof t}:function(t){return t&&"function"==typeof Symbol&&t.constructor===Symbol&&t!==Symbol.prototype?"symbol":typeof t},_typeof(t)}!function(t,n){"object"===("undefined"==typeof exports?"undefined":_typeof(exports))&&"undefined"!=typeof module?n(exports):"function"==typeof define&&define.amd?define(["exports"],n):n((t="undefined"!=typeof globalThis?globalThis:t||self).idbKeyval={})}(this,(function(t){"use strict";function n(t){return new Promise((function(n,r){t.oncomplete=t.onsuccess=function(){return n(t.result)},t.onabort=t.onerror=function(){return r(t.error)}}))}function r(t,r){var e=indexedDB.open(t);e.onupgradeneeded=function(){return e.result.createObjectStore(r)};var o=n(e);return function(t,n){return o.then((function(e){return n(e.transaction(r,t).objectStore(r))}))}}var e;function o(){return e||(e=r("keyval-store","keyval")),e}function u(t,r){return t.openCursor().onsuccess=function(){this.result&&(r(this.result),this.result.continue())},n(t.transaction)}t.clear=function(){var t=arguments.length>0&&void 0!==arguments[0]?arguments[0]:o();return t("readwrite",(function(t){return t.clear(),n(t.transaction)}))},t.createStore=r,t.del=function(t){var r=arguments.length>1&&void 0!==arguments[1]?arguments[1]:o();return r("readwrite",(function(r){return r.delete(t),n(r.transaction)}))},t.delMany=function(t){var r=arguments.length>1&&void 0!==arguments[1]?arguments[1]:o();return r("readwrite",(function(r){return t.forEach((function(t){return r.delete(t)})),n(r.transaction)}))},t.entries=function(){var t=arguments.length>0&&void 0!==arguments[0]?arguments[0]:o();return t("readonly",(function(r){if(r.getAll&&r.getAllKeys)return Promise.all([n(r.getAllKeys()),n(r.getAll())]).then((function(t){var n=_slicedToArray(t,2),r=n[0],e=n[1];return r.map((function(t,n){return[t,e[n]]}))}));var e=[];return t("readonly",(function(t){return u(t,(function(t){return e.push([t.key,t.value])})).then((function(){return e}))}))}))},t.get=function(t){var r=arguments.length>1&&void 0!==arguments[1]?arguments[1]:o();return r("readonly",(function(r){return n(r.get(t))}))},t.getMany=function(t){var r=arguments.length>1&&void 0!==arguments[1]?arguments[1]:o();return r("readonly",(function(r){return Promise.all(t.map((function(t){return n(r.get(t))})))}))},t.keys=function(){var t=arguments.length>0&&void 0!==arguments[0]?arguments[0]:o();return t("readonly",(function(t){if(t.getAllKeys)return n(t.getAllKeys());var r=[];return u(t,(function(t){return r.push(t.key)})).then((function(){return r}))}))},t.promisifyRequest=n,t.set=function(t,r){var e=arguments.length>2&&void 0!==arguments[2]?arguments[2]:o();return e("readwrite",(function(e){return e.put(r,t),n(e.transaction)}))},t.setMany=function(t){var r=arguments.length>1&&void 0!==arguments[1]?arguments[1]:o();return r("readwrite",(function(r){return t.forEach((function(t){return r.put(t[1],t[0])})),n(r.transaction)}))},t.update=function(t,r){var e=arguments.length>2&&void 0!==arguments[2]?arguments[2]:o();return e("readwrite",(function(e){return new Promise((function(o,u){e.get(t).onsuccess=function(){try{e.put(r(this.result),t),o(n(e.transaction))}catch(t){u(t)}}}))}))},t.values=function(){var t=arguments.length>0&&void 0!==arguments[0]?arguments[0]:o();return t("readonly",(function(t){if(t.getAll)return n(t.getAll());var r=[];return u(t,(function(t){return r.push(t.value)})).then((function(){return r}))}))},Object.defineProperty(t,"__esModule",{value:!0})}));
+
+/**
+ * Custom IDB Convenience Functions Wrapper
+ **/
+const IDB = (function () {
+  let { get, del, entries, update, keys } = window.idbKeyval;
+
+  return {
+    async set(key, newValue) {
+      let changeObj = {};
+      await update(key, (oldValue) => {
+        if (oldValue != null) changeObj.oldValue = oldValue;
+        changeObj.newValue = newValue;
+        return newValue;
+      });
+      return changeObj;
+    },
+
+    get(key, defaultValue) {
+      return get(key).then((resp) => {
+        return defaultValue && resp == null ? defaultValue : resp;
+      });
+    },
+
+    del(key) {
+      return del(key);
+    },
+
+    find(keyRegExp, includeValues = false) {
+      if (!(keyRegExp instanceof RegExp)) throw new Error("Invalid RegExp");
+
+      if (!includeValues)
+        return keys().then((allKeys) =>
+          allKeys.filter((key) => keyRegExp.test(key))
+        );
+
+      return entries().then((allItems) => {
+        const matchingKeys = allItems.filter((keyVal) =>
+          keyRegExp.test(keyVal[0])
+        );
+        return matchingKeys.reduce((obj, keyVal) => {
+          const [key, val] = keyVal;
+          obj[key] = val;
+          return obj;
+        }, {});
+      });
+    },
+  };
+})();

assets/offline/index.html

@@ -0,0 +1,155 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta
+      name="viewport"
+      content="width=device-width, initial-scale=0.90, user-scalable=no, viewport-fit=cover"
+    />
+    <meta name="apple-mobile-web-app-capable" content="yes" />
+    <meta
+      name="apple-mobile-web-app-status-bar-style"
+      content="black-translucent"
+    />
+    <meta
+      name="theme-color"
+      content="#F3F4F6"
+      media="(prefers-color-scheme: light)"
+    />
+    <meta
+      name="theme-color"
+      content="#1F2937"
+      media="(prefers-color-scheme: dark)"
+    />
+
+    <title>Book Manager - Offline</title>
+
+    <link rel="manifest" href="/manifest.json" />
+    <link rel="stylesheet" href="/assets/style.css" />
+
+    <script src="/assets/js/idb-keyval.js"></script>
+    <script src="/assets/offline/index.js"></script>
+
+    <style>
+      /* ----------------------------- */
+      /* -------- PWA Styling -------- */
+      /* ----------------------------- */
+      html,
+      body {
+        overscroll-behavior-y: none;
+        margin: 0px;
+      }
+
+      html {
+        height: calc(100% + env(safe-area-inset-bottom));
+        padding: env(safe-area-inset-top) env(safe-area-inset-right) 0
+          env(safe-area-inset-left);
+      }
+
+      main {
+        height: calc(100dvh - 4rem - env(safe-area-inset-top));
+      }
+
+      #container {
+        padding-bottom: calc(5em + env(safe-area-inset-bottom) * 2);
+      }
+
+      /* No Scrollbar - IE, Edge, Firefox */
+      * {
+        -ms-overflow-style: none;
+        scrollbar-width: none;
+      }
+
+      /* No Scrollbar - WebKit */
+      *::-webkit-scrollbar {
+        display: none;
+      }
+
+      .css-button:checked + div {
+        display: block;
+        opacity: 1;
+      }
+
+      .css-button + div {
+        display: none;
+        opacity: 0;
+      }
+
+      .css-button:checked + div + label {
+        display: none;
+      }
+    </style>
+  </head>
+  <body class="bg-gray-100 dark:bg-gray-800">
+    <div class="flex items-center justify-between w-full h-16">
+      <h1 class="text-xl font-bold dark:text-white px-6 lg:ml-48">
+        Offline Documents
+      </h1>
+    </div>
+
+    <main class="relative overflow-hidden">
+      <div
+        id="container"
+        class="h-[100dvh] px-4 overflow-auto md:px-6 lg:mx-48"
+      >
+        <div class="grid grid-cols-1 gap-4 md:grid-cols-2 lg:grid-cols-3"></div>
+
+        <div
+          class="fixed bottom-6 right-6 rounded-full flex items-center justify-center"
+        >
+          <input
+            type="checkbox"
+            id="add-file-button"
+            class="hidden css-button"
+          />
+          <div
+            class="rounded p-4 bg-gray-800 dark:bg-gray-200 text-white dark:text-black w-72 text-sm flex flex-col gap-2"
+          >
+            <div class="flex flex-col gap-2">
+              <input
+                type="file"
+                accept=".epub"
+                id="document_file"
+                name="document_file"
+              />
+              <button
+                class="font-medium px-2 py-1 text-gray-800 bg-gray-500 dark:text-white hover:bg-gray-100 dark:hover:bg-gray-800"
+              >
+                Add File
+              </button>
+            </div>
+            <label for="add-file-button">
+              <div
+                class="w-full text-center cursor-pointer font-medium mt-2 px-2 py-1 text-gray-800 bg-gray-500 dark:text-white hover:bg-gray-100 dark:hover:bg-gray-800"
+              >
+                Cancel
+              </div>
+            </label>
+          </div>
+          <label
+            class="w-16 h-16 bg-gray-800 dark:bg-gray-200 rounded-full flex items-center justify-center opacity-30 hover:opacity-100 transition-all duration-200 cursor-pointer"
+            for="add-file-button"
+          >
+            <svg
+              width="34"
+              height="34"
+              class="text-gray-200 dark:text-gray-600"
+              viewBox="0 0 24 24"
+              fill="currentColor"
+              xmlns="http://www.w3.org/2000/svg"
+            >
+              <path
+                fill-rule="evenodd"
+                clip-rule="evenodd"
+                d="M12 15.75C12.4142 15.75 12.75 15.4142 12.75 15V4.02744L14.4306 5.98809C14.7001 6.30259 15.1736 6.33901 15.4881 6.06944C15.8026 5.79988 15.839 5.3264 15.5694 5.01191L12.5694 1.51191C12.427 1.34567 12.2189 1.25 12 1.25C11.7811 1.25 11.573 1.34567 11.4306 1.51191L8.43056 5.01191C8.16099 5.3264 8.19741 5.79988 8.51191 6.06944C8.8264 6.33901 9.29988 6.30259 9.56944 5.98809L11.25 4.02744L11.25 15C11.25 15.4142 11.5858 15.75 12 15.75Z"
+              />
+              <path
+                d="M16 9C15.2978 9 14.9467 9 14.6945 9.16851C14.5853 9.24148 14.4915 9.33525 14.4186 9.44446C14.25 9.69667 14.25 10.0478 14.25 10.75L14.25 15C14.25 16.2426 13.2427 17.25 12 17.25C10.7574 17.25 9.75004 16.2426 9.75004 15L9.75004 10.75C9.75004 10.0478 9.75004 9.69664 9.58149 9.4444C9.50854 9.33523 9.41481 9.2415 9.30564 9.16855C9.05341 9 8.70227 9 8 9C5.17157 9 3.75736 9 2.87868 9.87868C2 10.7574 2 12.1714 2 14.9998V15.9998C2 18.8282 2 20.2424 2.87868 21.1211C3.75736 21.9998 5.17157 21.9998 8 21.9998H16C18.8284 21.9998 20.2426 21.9998 21.1213 21.1211C22 20.2424 22 18.8282 22 15.9998V14.9998C22 12.1714 22 10.7574 21.1213 9.87868C20.2426 9 18.8284 9 16 9Z"
+              />
+            </svg>
+          </label>
+        </div>
+      </div>
+    </main>
+  </body>
+</html>

assets/offline/index.js

@@ -0,0 +1,195 @@
+const BASE_ITEM = `
+  <div class="w-full relative">
+    <div class="flex gap-4 w-full h-full p-4 bg-white shadow-lg dark:bg-gray-700 rounded">
+      <div class="min-w-fit my-auto h-48 relative">
+	<a href="#">
+	  <img class="rounded object-cover h-full" src="/assets/images/no-cover.jpg"></img>
+	</a>
+      </div>
+      <div class="flex flex-col justify-around dark:text-white w-full text-sm">
+	<div class="inline-flex shrink-0 items-center">
+	  <div>
+	      <p class="text-gray-400">Title</p>
+	      <p class="font-medium">
+		N/A
+	      </p>
+	  </div>
+	</div>
+	<div class="inline-flex shrink-0 items-center">
+	  <div>
+	      <p class="text-gray-400">Author</p>
+	      <p class="font-medium">
+		N/A
+	      </p>
+	  </div>
+	</div>
+	<div class="inline-flex shrink-0 items-center">
+	  <div>
+	      <p class="text-gray-400">Progress</p>
+	      <p class="font-medium">
+	      0%
+	      </p>
+	  </div>
+	</div>
+      </div>
+      <div class="absolute flex flex-col gap-2 right-4 bottom-4 text-gray-500 dark:text-gray-400">
+	<a href="#">
+	  <svg
+	    width="24"
+	    height="24"
+	    class="cursor-pointer hover:text-gray-800 dark:hover:text-gray-100"
+	    viewBox="0 0 24 24"
+	    fill="currentColor"
+	    xmlns="http://www.w3.org/2000/svg"
+	  >
+	    <path
+	      fill-rule="evenodd"
+	      clip-rule="evenodd"
+	      d="M2 12C2 7.28595 2 4.92893 3.46447 3.46447C4.92893 2 7.28595 2 12 2C16.714 2 19.0711 2 20.5355 3.46447C22 4.92893 22 7.28595 22 12C22 16.714 22 19.0711 20.5355 20.5355C19.0711 22 16.714 22 12 22C7.28595 22 4.92893 22 3.46447 20.5355C2 19.0711 2 16.714 2 12ZM12 6.25C12.4142 6.25 12.75 6.58579 12.75 7V12.1893L14.4697 10.4697C14.7626 10.1768 15.2374 10.1768 15.5303 10.4697C15.8232 10.7626 15.8232 11.2374 15.5303 11.5303L12.5303 14.5303C12.3897 14.671 12.1989 14.75 12 14.75C11.8011 14.75 11.6103 14.671 11.4697 14.5303L8.46967 11.5303C8.17678 11.2374 8.17678 10.7626 8.46967 10.4697C8.76256 10.1768 9.23744 10.1768 9.53033 10.4697L11.25 12.1893V7C11.25 6.58579 11.5858 6.25 12 6.25ZM8 16.25C7.58579 16.25 7.25 16.5858 7.25 17C7.25 17.4142 7.58579 17.75 8 17.75H16C16.4142 17.75 16.75 17.4142 16.75 17C16.75 16.5858 16.4142 16.25 16 16.25H8Z"
+	    />
+	  </svg>
+	</a>
+      </div>
+    </div>
+  </div>`;
+
+const GET_SW_CACHE = "GET_SW_CACHE";
+const DEL_SW_CACHE = "DEL_SW_CACHE";
+
+async function initOffline() {
+  if (document.location.pathname !== "/offline")
+    window.history.replaceState(null, null, "/offline");
+
+  await SW.install().catch((e) => {
+    console.log("Service Worker Install Error:", e);
+  });
+  console.log("Registered");
+  getCachedDocuments().then(populateDOM);
+}
+
+/**
+ * Ask service worker for list of cached documents.
+ **/
+async function getCachedDocuments() {
+  let cachedDocuments = await IDB.find(/^DOCUMENT-/, true);
+  let cachedSWData = await SW.send({ type: GET_SW_CACHE });
+  return cachedSWData;
+}
+
+async function sendSWMessage(data) {
+  let swReg = await navigator.serviceWorker.ready;
+  if (!swReg.active) return;
+
+  function randomID() {
+    return "00000000000000000000000000000000".replace(/[018]/g, (c) =>
+      (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4))))
+        .toString(16)
+        .toUpperCase()
+    );
+  }
+
+  let id = randomID();
+  navigator.serviceWorker.addEventListener(id, (event) => {
+    console.log("Response:", event);
+    navigator.serviceWorker.removeEventListener(id);
+  });
+
+  swReg.active.postMessage({ id, data });
+}
+
+/**
+ * Populate DOM with cached documents.
+ **/
+function populateDOM(data) {
+  let allDocuments = document.querySelector("#container div");
+
+  data.forEach((item) => {
+    // Create Main Element
+    let baseEl = document.createElement("div");
+    baseEl.innerHTML = BASE_ITEM;
+    baseEl = baseEl.firstElementChild;
+
+    // Get Elements
+    let coverEl = baseEl.querySelector("a img");
+    let [titleEl, authorEl, percentageEl] = baseEl.querySelectorAll("p + p");
+    let downloadEl = baseEl.querySelector("svg").parentElement;
+
+    // Set Variables
+    downloadEl.setAttribute("href", "/documents/" + item.id + "/file");
+    coverEl.setAttribute("src", "/documents/" + item.id + "/cover");
+    coverEl.parentElement.setAttribute("href", "/reader?id=" + item.id);
+    titleEl.textContent = item.title;
+    authorEl.textContent = item.author;
+    percentageEl.textContent = item.percentage + "%";
+
+    allDocuments.append(baseEl);
+  });
+}
+
+/**
+ * Allow adding file to offline reader. Add to IndexedDB,
+ * and later upload? Add style indicating external file?
+ **/
+function handleFileAdd() {}
+
+const SW = (function () {
+  // Helper Function
+  function randomID() {
+    return "00000000000000000000000000000000".replace(/[018]/g, (c) =>
+      (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4))))
+        .toString(16)
+        .toUpperCase()
+    );
+  }
+
+  // Variables
+  let swInstance = null;
+  let outstandingMessages = {};
+
+  navigator.serviceWorker.addEventListener("message", ({ data }) => {
+    let { id } = data;
+    data = data.data;
+
+    console.log("SW Message:", id, data);
+    if (!outstandingMessages[id])
+      return console.warn("Invalid Outstanding Message:", { id, data });
+
+    outstandingMessages[id](data);
+    delete outstandingMessages[id];
+  });
+
+  return {
+    async install() {
+      // Register Service Worker
+      swInstance = await navigator.serviceWorker.register("/sw.js");
+      console.log(swInstance);
+      swInstance.onupdatefound = (data) => console.log("Update Found:", data);
+
+      // Wait for Registration / Update
+      let serviceWorker =
+        swInstance.installing || swInstance.waiting || swInstance.active;
+      if (serviceWorker.state == "activated") return;
+      await new Promise((resolve) => {
+        serviceWorker.onstatechange = (data) => {
+          console.log("State Change:", serviceWorker.state);
+          if (serviceWorker.state == "activated") resolve();
+        };
+      });
+    },
+
+    send(data) {
+      if (!swInstance?.active) return Promise.reject("Inactive Service Worker");
+      let id = randomID();
+
+      let msgPromise = new Promise((resolve) => {
+        outstandingMessages[id] = resolve;
+      });
+
+      swInstance.active.postMessage({ id, data });
+      return msgPromise;
+    },
+  };
+})();
+
+// Initialize
+window.addEventListener("DOMContentLoaded", initOffline);

assets/reader/index.html

@@ -14,11 +14,21 @@
     />
     <meta name="theme-color" content="#D2B48C" />
 
-    <title>Book Manager - {{block "title" .}}{{end}}</title>
+    <title>Book Manager - Reader</title>
 
     <link rel="manifest" href="/manifest.json" />
     <link rel="stylesheet" href="/assets/style.css" />
 
+    <!-- Libraries -->
+    <script src="/assets/js/platform.js"></script>
+    <script src="/assets/js/jszip.min.js"></script>
+    <script src="/assets/js/epub.min.js"></script>
+    <script src="/assets/js/no-sleep.js"></script>
+    <script src="/assets/js/idb-keyval.js"></script>
+
+    <!-- Reader -->
+    <script src="/assets/reader/index.js"></script>
+
     <style>
       html,
       body {
@@ -66,7 +76,7 @@
       >
         <div class="w-full h-32 flex items-center justify-around relative">
           <div class="text-gray-500 absolute top-6 left-4 flex flex-col gap-4">
-            <a href="../{{ .Data.ID }}">
+            <a href="#">
               <svg
                 width="32"
                 height="32"
@@ -101,8 +111,11 @@
 
           <div class="flex gap-10 h-full p-4 pl-14 rounded">
             <div class="h-full my-auto relative">
-              <a href="../{{ .Data.ID }}">
+              <a href="#">
-                <img class="rounded object-cover h-full" src="./cover" />
+                <img
+                  class="rounded object-cover h-full"
+                  src="/assets/images/no-cover.jpg"
+                />
               </a>
             </div>
             <div class="flex gap-7 justify-around dark:text-white text-sm">
@@ -113,7 +126,7 @@
                     <p
                       class="font-medium whitespace-nowrap text-ellipsis overflow-hidden max-w-[50dvw]"
                     >
-                      {{ or .Data.Title "N/A" }}
+                      "N/A"
                     </p>
                   </div>
                 </div>
@@ -123,7 +136,7 @@
                     <p
                       class="font-medium whitespace-nowrap text-ellipsis overflow-hidden max-w-[50dvw]"
                     >
-                      {{ or .Data.Author "N/A" }}
+                      "N/A"
                     </p>
                   </div>
                 </div>
@@ -240,7 +253,7 @@
           </div>
         </div>
       </div>
-      {{block "content" .}}{{end}}
+      <div id="viewer" class="w-full h-full"></div>
     </main>
   </body>
 </html>

assets/reader/index.js

@@ -1,6 +1,51 @@
 const THEMES = ["light", "tan", "blue", "gray", "black"];
 const THEME_FILE = "/assets/reader/readerThemes.css";
 
+async function initReader() {
+  let documentData;
+  let filePath;
+
+  const urlParams = new URLSearchParams(window.location.search);
+  const documentID = urlParams.get("id");
+  const localID = urlParams.get("local");
+
+  if (documentID) {
+    // Get Server / Cached Document
+    let progressResp = await fetch("/documents/" + documentID + "/progress");
+    documentData = await progressResp.json();
+    filePath = "/documents/" + documentID + "/file";
+  } else if (localID) {
+    // Get Local Document
+    // TODO:
+    //   - IDB FileID
+    //   - IDB Metadata
+  } else {
+    throw new Error("Invalid");
+  }
+
+  populateMetadata(documentData);
+  window.currentReader = new EBookReader(filePath, documentData);
+}
+
+function populateMetadata(data) {
+  let documentLocation = data.id.startsWith("local-")
+    ? "/offline"
+    : "/documents/" + data.id;
+
+  let documentCoverLocation = data.id.startsWith("local-")
+    ? "/assets/images/no-cover.jpg"
+    : "/documents/" + data.id + "/cover";
+
+  let [backEl, coverEl] = document.querySelectorAll("a");
+  backEl.setAttribute("href", documentLocation);
+  coverEl.setAttribute("href", documentLocation);
+  coverEl.firstElementChild.setAttribute("src", documentCoverLocation);
+
+  let [titleEl, authorEl] = document.querySelectorAll("#top-bar p + p");
+  titleEl.innerText = data.title;
+  authorEl.innerText = data.author;
+}
+
 class EBookReader {
   bookState = {
     currentWord: 0,
@@ -13,6 +58,9 @@ class EBookReader {
   };
 
   constructor(file, bookState) {
+    // Save IDB Cache
+    IDB.set("DOCUMENT-" + bookState.id, bookState);
+
     // Set Variables
     Object.assign(this.bookState, bookState);
 
@@ -61,7 +109,7 @@ class EBookReader {
 
       // Get Stats
       let stats = this.getBookStats();
-      this.updateBookStats(stats);
+      this.updateBookStatElements(stats);
     }.bind(this);
 
     // Register Content Hook
@@ -381,25 +429,41 @@ class EBookReader {
       // ------------------------------------------------ //
       // --------------- Bottom & Top Bar --------------- //
       // ------------------------------------------------ //
-      let emSize = parseFloat(getComputedStyle(renderDoc.body).fontSize);
+      renderDoc.addEventListener(
-      renderDoc.addEventListener("click", function (event) {
+        "click",
-        let barPixels = emSize * 5;
+        function (event) {
+          // Get Window Dimensions
+          let windowWidth = window.innerWidth;
+          let windowHeight = window.innerHeight;
 
-        let top = barPixels;
+          // Calculate X & Y Hot Zones
-        let bottom = window.innerHeight - top;
+          let barPixels = windowHeight * 0.2;
+          let pagePixels = windowWidth * 0.2;
 
-        let left = barPixels / 2;
+          // Calculate Top & Bottom Thresholds
-        let right = window.innerWidth - left;
+          let top = barPixels;
+          let bottom = window.innerHeight - top;
 
-        if (event.clientY < top) handleSwipeDown();
+          // Calculate Left & Right Thresholds
-        else if (event.clientY > bottom) handleSwipeUp();
+          let left = pagePixels;
-        else if (event.screenX < left) prevPage();
+          let right = windowWidth - left;
-        else if (event.screenX > right) nextPage();
+
-        else {
+          // Calculate Relative Coords
-          bottomBar.classList.remove("bottom-0");
+          let leftOffset = this.views().container.scrollLeft;
-          topBar.classList.remove("top-0");
+          let yCoord = event.clientY;
-        }
+          let xCoord = event.clientX - leftOffset;
-      });
+
+          // Handle Event
+          if (yCoord < top) handleSwipeDown();
+          else if (yCoord > bottom) handleSwipeUp();
+          else if (xCoord < left) prevPage();
+          else if (xCoord > right) nextPage();
+          else {
+            bottomBar.classList.remove("bottom-0");
+            topBar.classList.remove("top-0");
+          }
+        }.bind(this)
+      );
 
       renderDoc.addEventListener(
         "wheel",
@@ -565,26 +629,8 @@ class EBookReader {
    * Progresses to the next page & monitors reading activity
    **/
   async nextPage() {
-    // Flush Activity
+    // Create Activity
-    this.flushActivity();
+    await this.createActivity();
-
-    // Get Elapsed Time
-    let elapsedTime = Date.now() - this.bookState.pageStart;
-
-    // Update Current Word
-    let pageWords = await this.getVisibleWordCount();
-    let startingWord = this.bookState.currentWord;
-    let percentRead = pageWords / this.bookState.words;
-    this.bookState.currentWord += pageWords;
-
-    // Add Read Event
-    this.bookState.readActivity.push({
-      percentRead,
-      startingWord,
-      pageWords,
-      elapsedTime,
-      startTime: this.bookState.pageStart,
-    });
 
     // Render Next Page
     await this.rendition.next();
@@ -594,24 +640,16 @@ class EBookReader {
 
     // Update Stats
     let stats = this.getBookStats();
-    this.updateBookStats(stats);
+    this.updateBookStatElements(stats);
 
-    // Update & Flush Progress
+    // Create Progress
-    let currentCFI = await this.rendition.currentLocation();
+    this.createProgress();
-    let { element, xpath } = await this.getXPathFromCFI(currentCFI.start.cfi);
-    this.bookState.progress = xpath;
-    this.bookState.progressElement = element;
-
-    this.flushProgress();
   }
 
   /**
    * Progresses to the previous page & monitors reading activity
    **/
   async prevPage() {
-    // Flush Activity
-    this.flushActivity();
-
     // Render Previous Page
     await this.rendition.prev();
 
@@ -624,14 +662,10 @@ class EBookReader {
 
     // Update Stats
     let stats = this.getBookStats();
-    this.updateBookStats(stats);
+    this.updateBookStatElements(stats);
 
-    // Update & Flush Progress
+    // Create Progress
-    let currentCFI = await this.rendition.currentLocation();
+    this.createProgress();
-    let { element, xpath } = await this.getXPathFromCFI(currentCFI.start.cfi);
-    this.bookState.progress = xpath;
-    this.bookState.progressElement = element;
-    this.flushProgress();
   }
 
   /**
@@ -652,88 +686,95 @@ class EBookReader {
     this.highlightPositionMarker();
   }
 
-  /**
+  async createActivity() {
-   * Normalize and flush activity
+    // WPM MAX & MIN
-   **/
-  async flushActivity() {
-    // Process & Reset Activity
-    let allActivity = this.bookState.readActivity;
-    this.bookState.readActivity = [];
-
     const WPM_MAX = 2000;
     const WPM_MIN = 100;
 
-    let normalizedActivity = allActivity
+    // Get Elapsed Time
-      // Exclude Fast WPM
+    let pageStart = this.bookState.pageStart;
-      .filter((item) => item.pageWords / (item.elapsedTime / 60000) < WPM_MAX)
+    let elapsedTime = Date.now() - pageStart;
-      .map((item) => {
-        let pageWPM = item.pageWords / (item.elapsedTime / 60000);
 
-        // Min WPM
+    // Update Current Word
-        if (pageWPM < WPM_MIN) {
+    let pageWords = await this.getVisibleWordCount();
-          // TODO - Exclude Event?
+    let startingWord = this.bookState.currentWord;
-          item.elapsedTime = (item.pageWords / WPM_MIN) * 60000;
+    let percentRead = pageWords / this.bookState.words;
-        }
+    this.bookState.currentWord += pageWords;
 
-        item.pages = Math.round(1 / item.percentRead);
+    let pageWPM = pageWords / (elapsedTime / 60000);
 
-        item.page = Math.round(
+    // Exclude Ridiculous WPM
-          (item.startingWord * item.pages) / this.bookState.words
+    // if (pageWPM >= WPM_MAX) return;
-        );
 
-        // Estimate Accuracy Loss (Debugging)
+    // Ensure WPM Minimum
-        // let wordLoss = Math.abs(
+    if (pageWPM < WPM_MIN) elapsedTime = (pageWords / WPM_MIN) * 60000;
-        //   item.pageWords - this.bookState.words / item.pages
-        // );
-        // console.log("Word Loss:", wordLoss);
 
-        return {
+    let totalPages = Math.round(1 / percentRead);
-          document: this.bookState.id,
-          duration: Math.round(item.elapsedTime / 1000),
-          start_time: Math.round(item.startTime / 1000),
-          page: item.page,
-          pages: item.pages,
-        };
-      });
 
-    if (normalizedActivity.length == 0) return;
+    let currentPage = Math.round(
-
+      (startingWord * totalPages) / this.bookState.words
-    console.log("Flushing Activity...");
+    );
 
     // Create Activity Event
     let activityEvent = {
       device_id: this.readerSettings.deviceID,
       device: this.readerSettings.deviceName,
-      activity: normalizedActivity,
+      activity: [
+        {
+          document: this.bookState.id,
+          duration: Math.round(elapsedTime / 1000),
+          start_time: Math.round(pageStart / 1000),
+          page: currentPage,
+          pages: totalPages,
+        },
+      ],
     };
 
-    // Flush Activity
+    // Flush -> Offline Cache IDB
-    fetch("/api/ko/activity", {
+    this.flushActivity(activityEvent).catch(async (e) => {
-      method: "POST",
+      console.error("Activity Flush Failed:", {
-      body: JSON.stringify(activityEvent),
+        error: e,
-    })
+        data: activityEvent,
-      .then(async (r) =>
+      });
-        console.log("Flushed Activity:", {
+
-          response: r,
+      // Get & Update Activity
-          json: await r.json(),
+      let existingActivity = await IDB.get("ACTIVITY", { activity: [] });
-          data: activityEvent,
+      existingActivity.device_id = activityEvent.device_id;
-        })
+      existingActivity.device = activityEvent.device;
-      )
+      existingActivity.activity.push(...activityEvent.activity);
-      .catch((e) =>
+
-        console.error("Activity Flush Failed:", {
+      // Update IDB
-          error: e,
+      await IDB.set("ACTIVITY", existingActivity);
-          data: activityEvent,
+    });
-        })
-      );
   }
 
   /**
-   * Flush progress to the API. Called when the page changes.
+   * Normalize and flush activity
    **/
-  async flushProgress() {
+  flushActivity(activityEvent) {
-    console.log("Flushing Progress...");
+    console.log("Flushing Activity...");
 
-    // Create Progress Event
+    // Flush Activity
+    return fetch("/api/ko/activity", {
+      method: "POST",
+      body: JSON.stringify(activityEvent),
+    }).then(async (r) =>
+      console.log("Flushed Activity:", {
+        response: r,
+        json: await r.json(),
+        data: activityEvent,
+      })
+    );
+  }
+
+  async createProgress() {
+    // Update Pointers
+    let currentCFI = await this.rendition.currentLocation();
+    let { element, xpath } = await this.getXPathFromCFI(currentCFI.start.cfi);
+    this.bookState.progress = xpath;
+    this.bookState.progressElement = element;
+
+    // Create Event
     let progressEvent = {
       document: this.bookState.id,
       device_id: this.readerSettings.deviceID,
@@ -745,24 +786,39 @@ class EBookReader {
       progress: this.bookState.progress,
     };
 
+    // Flush -> Offline Cache IDB
+    this.flushProgress(progressEvent).catch(async (e) => {
+      console.error("Progress Flush Failed:", {
+        error: e,
+        data: progressEvent,
+      });
+
+      // Get & Update Activity
+      let existingProgress = await IDB.get("PROGRESS", []);
+      existingProgress.push(progressEvent);
+
+      // Update IDB
+      await IDB.set("PROGRESS", existingProgress);
+    });
+  }
+
+  /**
+   * Flush progress to the API. Called when the page changes.
+   **/
+  flushProgress(progressEvent) {
+    console.log("Flushing Progress...");
+
     // Flush Progress
-    fetch("/api/ko/syncs/progress", {
+    return fetch("/api/ko/syncs/progress", {
       method: "PUT",
       body: JSON.stringify(progressEvent),
-    })
+    }).then(async (r) =>
-      .then(async (r) =>
+      console.log("Flushed Progress:", {
-        console.log("Flushed Progress:", {
+        response: r,
-          response: r,
+        json: await r.json(),
-          json: await r.json(),
+        data: progressEvent,
-          data: progressEvent,
+      })
-        })
+    );
-      )
-      .catch((e) =>
-        console.error("Progress Flush Failed:", {
-          error: e,
-          data: progressEvent,
-        })
-      );
   }
 
   /**
@@ -812,7 +868,7 @@ class EBookReader {
   /**
    * Update elements with stats
    **/
-  updateBookStats(data) {
+  updateBookStatElements(data) {
     if (!data) return;
 
     let chapterStatus = document.querySelector("#chapter-status");
@@ -1076,3 +1132,5 @@ class EBookReader {
     );
   }
 }
+
+document.addEventListener("DOMContentLoaded", initReader);

assets/style.css

@@ -2046,6 +2046,11 @@ video {
 }
 
 @media (min-width: 1024px) {
+  .lg\:mx-48 {
+    margin-left: 12rem;
+    margin-right: 12rem;
+  }
+
   .lg\:ml-44 {
     margin-left: 11rem;
   }

assets/sw.js

@@ -0,0 +1,161 @@
+// Local Consts
+const SW_VERSION = 1;
+const SW_CACHE_NAME = "OFFLINE_V1";
+
+// Message Consts
+const PURGE_SW_CACHE = "PURGE_SW_CACHE";
+const DEL_SW_CACHE = "DEL_SW_CACHE";
+const GET_SW_CACHE = "GET_SW_CACHE";
+const GET_SW_VERSION = "GET_SW_VERSION";
+
+// Assets
+const ASSETS_DOCUMENT = /^\/documents\/[a-zA-Z0-9]{32}\/(cover|file|progress)$/;
+const ASSETS_OFFLINE = [
+  // Offline Resources
+  "/offline",
+  "/assets/offline/index.js",
+  "/assets/reader/index.js",
+  "/assets/images/no-cover.jpg",
+
+  // App Style
+  "/manifest.json",
+  "/assets/style.css",
+
+  // Reader & Offline Libraries
+  "/assets/js/platform.js",
+  "/assets/js/jszip.min.js",
+  "/assets/js/epub.min.js",
+  "/assets/js/no-sleep.js",
+  "/assets/js/idb-keyval.js",
+];
+
+function wantCache(request) {
+  let urlPath = new URL(request.url).pathname;
+  if (ASSETS_OFFLINE.includes(urlPath)) return true;
+  if (urlPath.match(ASSETS_DOCUMENT)) return true;
+  return false;
+}
+
+/**
+ * Nuke Cache
+ **/
+function purgeCache() {
+  return caches.keys().then(function (names) {
+    for (let name of names) caches.delete(name);
+  });
+}
+
+/**
+ * Update Cache
+ **/
+async function updateCache(request) {
+  let cache = await caches.open(SW_CACHE_NAME);
+
+  console.log("UPDATING CACHE:", request.url);
+
+  return fetch(request).then((response) => {
+    const resClone = response.clone();
+    if (response.status < 400) cache.put(request, resClone);
+    return response;
+  });
+}
+
+/**
+ * Pre-Cache Resources on Install
+ **/
+function cacheOfflineResources() {
+  return caches.open(SW_CACHE_NAME).then(function (cache) {
+    return cache.addAll(ASSETS_OFFLINE);
+  });
+}
+
+/**
+ * Install & Update Listener -> Cache Offline Resources
+ **/
+self.addEventListener("install", function (event) {
+  console.log("INSTALL:", event);
+  event.waitUntil(cacheOfflineResources());
+});
+
+/**
+ * Message Listener -> Communication Channel Page <-> SW
+ **/
+self.addEventListener("message", (event) => {
+  console.log("MESSAGE:", event);
+  let { id, data } = event.data;
+
+  if (data.type === GET_SW_VERSION) {
+    event.source.postMessage({ id, data: SW_VERSION });
+  } else if (data.type === PURGE_SW_CACHE) {
+    purgeCache()
+      .then(() => event.source.postMessage({ id, data: "SUCCESS" }))
+      .catch(() => event.source.postMessage({ id, data: "FAILURE" }));
+  } else if (data.type === GET_SW_CACHE) {
+    caches.open(SW_CACHE_NAME).then(async (cache) => {
+      let allKeys = await cache.keys();
+
+      let docResources = allKeys
+        .map((item) => new URL(item.url).pathname)
+        .filter((item) => item.startsWith("/documents/"));
+
+      let documentIDs = Array.from(
+        new Set(docResources.map((item) => item.split("/")[2]))
+      );
+
+      let cachedDocuments = await Promise.all(
+        documentIDs
+          .filter(
+            (id) =>
+              docResources.includes("/documents/" + id + "/file") &&
+              docResources.includes("/documents/" + id + "/progress")
+          )
+          .map(async (id) => {
+            let resp = await cache.match("/documents/" + id + "/progress");
+            return resp.json();
+          })
+      );
+
+      event.source.postMessage({ id, data: cachedDocuments });
+    });
+
+    // TODO
+  } else if (data.type === DEL_SW_CACHE) {
+    // TODO
+  } else {
+    event.source.postMessage({ id, data: { pong: 1 } });
+  }
+});
+
+/**
+ * Fetch Listener -> Cache
+ *   - Covers
+ *   - Files
+ *   - Assets (Styles, JS Libraries)
+ *
+ * NOTE: We do not cache regular app resources. We will fallback to the
+ * offline reader.
+ **/
+self.addEventListener("fetch", (event) => {
+  event.respondWith(
+    (async function () {
+      // Bypass Lazy Caching
+      if (event.request.url.endsWith("/progress")) {
+        return updateCache(event.request).catch((e) =>
+          caches.match(event.request)
+        );
+      }
+
+      // Get Potential Cache
+      let cachedResponse = await caches.match(event.request);
+
+      // Update Cache Asynchronously (If Wanted)
+      let newResponse = (
+        wantCache(event.request)
+          ? updateCache(event.request)
+          : fetch(event.request)
+      ).catch((e) => caches.match("/offline"));
+
+      return cachedResponse || newResponse;
+    })()
+  );
+});

client/syncninja.koplugin/main.lua

@@ -649,7 +649,7 @@ end
 function SyncNinja:checkDocuments(interactive)
     logger.dbg("SyncNinja: checkDocuments")
 
-    -- ensure document sync enabled
+    -- Ensure Document Sync Enabled
     if self.settings.sync_documents ~= true then return end
 
     -- API Request Data
@@ -723,6 +723,8 @@ function SyncNinja:downloadDocuments(doc_metadata, interactive)
     logger.dbg("SyncNinja: downloadDocuments")
 
     -- TODO
+    --   - OPDS Sufficient?
+    --   - Auto Configure OPDS?
 end
 
 function SyncNinja:uploadDocumentMetadata(doc_metadata, interactive)

tailwind.config.js

@@ -1,6 +1,10 @@
 /** @type {import('tailwindcss').Config} */
 module.exports = {
-  content: ["./templates/**/*.html", "./assets/reader/index.js"],
+  content: [
+    "./templates/**/*.html",
+    "./assets/offline/*.{html,js}",
+    "./assets/reader/*.{html,js}",
+  ],
   theme: {
     extend: {},
   },

templates/document.html

@@ -17,7 +17,7 @@
 
       {{ if .Data.Filepath }}
       <a
-	href="./{{ .Data.ID }}/reader"
+	href="/reader?id={{ .Data.ID }}"
 	class="z-10 text-white bg-blue-700 hover:bg-blue-800 focus:ring-4 focus:ring-blue-300 font-medium rounded text-sm text-center py-1 dark:bg-blue-600 dark:hover:bg-blue-700 focus:outline-none dark:focus:ring-blue-800"
       >Read</a>
       {{ end }}

templates/login.html

@@ -134,19 +134,19 @@
       >
         <img
           class="w-full h-screen object-cover ease-in-out top-0 left-0"
-          src="/assets/book1.jpg"
+          src="/assets/images/book1.jpg"
         />
         <img
           class="w-full h-screen object-cover ease-in-out top-0 left-0"
-          src="/assets/book2.jpg"
+          src="/assets/images/book2.jpg"
         />
         <img
           class="w-full h-screen object-cover ease-in-out top-0 left-0"
-          src="/assets/book3.jpg"
+          src="/assets/images/book3.jpg"
         />
         <img
           class="w-full h-screen object-cover ease-in-out top-0 left-0"
-          src="/assets/book4.jpg"
+          src="/assets/images/book4.jpg"
         />
       </div>
     </div>

templates/reader.html

@@ -1,22 +0,0 @@
-{{template "base.html" .}} {{define "title"}}Reader{{end}} {{define "header"}}
-<a href="../">Documents</a>
-{{end}} {{define "content"}}
-
-<div id="viewer" class="w-full h-full"></div>
-
-<script src="../../assets/reader/platform.js"></script>
-<script src="../../assets/reader/jszip.min.js"></script>
-<script src="../../assets/reader/epub.min.js"></script>
-<script src="../../assets/reader/no-sleep.js"></script>
-<script src="../../assets/reader/index.js"></script>
-<script>
-  let currentReader = new EBookReader("./file", {
-    id: "{{ .Data.ID }}",
-    words: {{ .Data.Words }},
-    pages: {{ .Data.Pages }},
-    progress: "{{ .Progress }}",
-    percentage: {{ .Data.Percentage }},
-    currentWord: {{ .Data.Percentage }} * ({{ .Data.Words }} / 100),
-  });
-</script>
-{{ end}}